Miniature implantable connectors

ABSTRACT

The invention discloses apparatus for connecting electrically conductive wire to a miniature, implantable sensor or stimulator device for detecting electrical signals or stimulating living tissue. The implantable device has an electrically conductive end on its case which is intimately connected to a doorknob electrode for communicating electrical signals between the living tissue and the device by a biocompatible wire. A spring clip removably attaches to the doorknob electrode so that the wire may be easily attached to the doorknob electrode during surgery. An insulating rubber boot, which may be silicone, surrounds the case end, doorknob electrode, and spring clip to isolate the living tissue from the conductive components. The components are all biocompatible materials.

This application claims the benefit of U.S. Provisional application No.60/299,106, filed Jun. 18, 2001.

FIELD OF THE INVENTION

This invention relates to a prosthetic medical device and methods, andmore particularly to methods of connecting electrical conducting wiresto a miniature implantable device to minimize risk to the living tissueduring and after surgery.

BACKGROUND OF THE INVENTION

Neurological disorders are often caused by neural impulses failing toreach their natural destination in otherwise functional body systems.Local nerves and muscles may function, but, for various reasons, such asinjury, stroke, or other cause, the stimulating nerve signals do notreach their natural destination. For example, paraplegic andquadriplegic animals have intact nerves connected to functioning musclesand only lack the brain-to-nerve link. Electrically stimulating thenerve or muscle can provide a useful muscle contraction.

Further, implanted devices may be sensors as well as stimulators. Ineither case, difficulties arise both in providing suitable, operablestimulators or sensors which are small in size and in passing sufficientenergy and control information to or from the device, with or withoutdirect connection, to satisfactorily operate them. Miniature monitoringand/or stimulating devices for implantation in a living body aredisclosed by Schulman, et al. (U.S. Pat. No. 6,164,284), Schulman, etal. (U.S. Pat. No. 6,185,452), and Schulman, et al. (U.S. Pat. No.6,208,894).

It must be assured that the electrical current flow does not damage theintermediate body cells or cause undesired stimulation. Anodic orcathodic deterioration of the stimulating electrodes must not occur.

In addition, at least one small stimulator or sensor disposed at variouslocations within the body may send or receive signals via electricalwires.

The implanted unit must be sealed to protect the internal componentsfrom the body's aggressive environment. If wires are attached to thestimulator, then these wires and the area of attachment must beelectrically insulated to prevent undesired electric signals frompassing to surrounding tissue.

Miniature stimulators offer the benefit of being locatable at a sitewithin the body where a larger stimulator cannot be placed because ofits size. The miniature stimulator may be placed into the body byinjection. The miniature stimulator offers other improvements overlarger stimulators in that they may be placed in the body with little orno negative cosmetic effect. There may be locations where theseminiature devices do not fit for which it is desired to send or receivesignals. Such locations include, but are not limited to, the tip of afinger for detection of a stimulating signal or near an eyelid forstimulating blinking. In such locations, the stimulator and itsassociated electronics are preferably located at a distance removed fromthe sensing or stimulating site within the body; thus creating the needto carry electrical signals from the detection or stimulation site tothe remote miniature stimulator, where the signal wire must be securelyfastened to the stimulator.

Further, the miniature stimulator may contain a power supply thatrequires periodic charging or require replacement, such as a battery.When this is the case, the actual stimulation or detection site may belocated remotely from the stimulator and may be located within the body,but removed a significant distance from the skin surface. By having theability to locate the miniature stimulator near the skin while thestimulation site is at some distance removed from the skin, theminiature stimulator and its associated electronics can be moreeffectively replaced by a surgical technique or more efficientlyrecharged through the skin by any of several known techniques, includingthe use of alternating magnetic fields. If the electronics package isreplaced surgically, then it is highly desirable to have the capabilityto reconnect the lead wires to the miniature stimulator via an easy,rapid and reliable method, as disclosed herein.

SUMMARY OF THE INVENTION

The instant invention relates to apparatus for connecting anelectrically conductive wire to a miniature, implantable sensor orstimulator. One structure is an Implantable miniature device having anelectrically conductive case end and a doorknob electrode coupled to itfor communicating electrical signals between living tissue and thedevice, a spring clip connector having an electrically conductive wirefor communicating the electrical signals between the doorknob electrodeand the tissue, and an insulating rubber boot surrounding theelectrically conductive case end, doorknob electrode and spring clip.

The spring clip connector may be formed of titanium, titanium alloy,platinum, iridium, platinum-indium, stainless steel, tantalum orniobium. The electrically conductive case end may be titanium, titaniumalloy, platinum, iridium, platinum-indium, zirconium, niobium, stainlesssteel, or tantalum. The electrically conductive case end may also beTi-6Al-4V. The doorknob electrode may be titanium, titanium alloy,platinum, iridium, platinum-iridium, stainless steel, tantalum orniobium. The insulating rubber boot may be silicone.

Another structure may be an implantable miniature device having anelectrically conductive case end and a doorknob electrode coupledthereto for communicating electrical signals between living tissue andthe device, where a spring clip connector having at least one prong forgrasping the doorknob electrode and adapted for attaching anelectrically conductive wire thereto for communicating the electricalsignals between the doorknob electrode and the tissue; and an insulatingrubber boot surrounding the electrically conductive case end, doorknobelectrode and spring clip. The spring clip connector may be formed oftitanium, titanium alloy, platinum, iridium, platinum-iridium, stainlesssteel, tantalum or niobium. The electrically conductive case end may betitanium, titanium alloy, platinum, iridium, platinum-iridium,zirconium, niobium, stainless steel, or tantalum. The electricallyconductive case end may be Ti-6Al-4V.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an implantable miniaturestimulator having at least one electrode.

It is an object of the invention to provide a method of connecting atleast one wire to a miniature stimulator in a body.

It is an object of the invention to increase the ease and safety of asurgeon making electrical connections for in vivo application of aminiature implantable stimulator.

It is an object of the invention to connect the electrode of a miniatureimplantable stimulator in a secure, safe and rapid fashion to electricalwires.

It is an object of the invention to electrically insulate the electrodeof an implantable miniature stimulator that is connected to anelectrical wire from the body environment in which it is implanted.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of the miniature stimulator with athreaded connector and nut.

FIG. 2 illustrates a perspective view of the miniature stimulator with abayonet connector and nut.

FIG. 3 illustrates a perspective view of the miniature stimulator with apin connector and nut.

FIG. 4 illustrates a perspective view of the smooth nut with a flare nutcap.

FIG. 5 is a cross-section through the flare nut wire insertion.

FIG. 6 is a cross-sectional view of the smooth cap with flare insertion.

FIG. 7 is a longitudinal section through the protective nut showing anoffset mounting hole.

FIG. 8 is a cross-section through the protective nut showing the offsetmounting hole.

FIG. 9 illustrates a stimulator with a hole and pin electrode.

FIG. 10 illustrates a stimulator with a hole and pin electrode and anelectrode plug.

FIG. 11 is a longitudinal cross-section of a threaded hole electrodewith plug.

FIG. 12 is a longitudinal cross-section of a threaded pin electrode withnut.

FIG. 13 is a longitudinal cross-section of a threaded pin electrode withnut and spade connector.

FIG. 14 illustrates a spade connector.

FIG. 15 illustrates a spade connector attached to a wire.

FIG. 15A illustrates a detailed section of the crimp of FIG. 15.

FIG. 15B illustrates a detailed section of an alternate crimp of FIG.15.

FIG. 16 is a longitudinal cross-section of an electrode hole with a plugand crush lip.

FIG. 17 illustrates a C-clamp.

FIG. 18 illustrates a pin electrode with a wire inserted.

FIG. 19 illustrates a protective nut with a crush lip.

FIG. 20 is a longitudinal section through threaded insert with a flareattachment.

FIG. 21 is a perspective view of a stimulator in combination with aflare nut.

FIG. 22 is a longitudinal section showing the flare nut with a rubberboot.

FIG. 22A is a section showing tie interaction with the rubber boot ofFIG. 22.

FIG. 23 is a top view of a disk-shaped miniature stimulator withelectrodes.

FIG. 24 is a side view of a disk-shaped miniature stimulator withelectrodes.

FIG. 25 illustrates a miniature stimulator annular electrode and asection through the annular nut.

FIG. 26 is an end view of the miniature stimulator with annularelectrodes.

FIG. 27 is an end view of the annular nut.

FIG. 28 is a longitudinal section through a miniature stimulator withannular electrodes and a section through the annular nut.

FIG. 29 illustrates an end view of a plug with wires.

FIG. 30 is a longitudinal cross-section through a plug with wiresinstalled in a hollow miniature stimulator.

FIG. 31 illustrates a perspective view of an electrically conductivedoorknob shaped electrode with spring clip connector and wire.

FIG. 32 is a perspective view of the electrically conductive doorknobshaped electrode.

FIG. 33 is a perspective view of the spring clip connector.

FIG. 34 is a longitudinal section through the doorknob shaped connectorwith a wire and rubber boot.

FIG. 35 is a longitudinal section through the doorknob shaped connectorwith crimped connector a wire and rubber boot.

FIG. 36 is longitudinal section through the snap-on cap connector withrubber boot.

FIG. 37 is longitudinal section through the elongated snap-on capconnector with rubber boot.

FIG. 37A details the tooth interaction with the slip-on cap of FIG. 37.

FIG. 38 is longitudinal section through the flat-bottomed slot connectorwith rubber boot.

FIG. 39 is a perspective view of the flat-bottomed slot connector.

FIG. 40 is a perspective view of the flat-bottomed snap-on cap.

FIG. 41 is a cross-section of the flat-bottomed slot connector in theengaged position.

FIG. 42 is a cross-section of the flat-bottomed slot snap-on cap in thedisengaged position.

FIG. 43 is a hand showing placement of an implantable miniature devicewith a wire lead that carries electrical signals to a fingertip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An implantable miniature stimulator 2 is illustrated in FIG. 1. FIG. 43represents a typical placement of the implantable miniature stimulator 2at a location that is remote from the site that is to be stimulated, inthis case a fingertip, where an electrically conductive wire 38 carriesthe electrical signal to an electrode 39 at the stimulation site.Typical dimensions for this device are about 5 to 60 mm in length andabout 1 to 6 mm in diameter. (See, for example, U.S. Pat. Nos.6,164,284, 6,185,452, and 6,208,894 which are incorporated herein byreference in their entirety.) While element 2 is generally described asa stimulator, it is recognized that the present invention is equallyapplicable when element 2 is operable as a sensor or as a stimulator anda sensor. Stimulator 2 includes insulating case 4, which typically ishollow and contains an electronics package and a power source, such as abattery, capacitor, magnetic field to electricity converter, andelectrically conductive case ends 6, each of which has an electricallyconductive electrode 8 which conducts electrical signals from astimulator and/or to a sensor, depending upon the design and function ofthat particular miniature stimulator 2. Stimulator 2 may have at leastone electrode, e.g., 2-8 or more, depending upon its particular designand function, although, for illustrative purposes, only two electrodesare shown in FIG. 1. Electrically conductive electrodes 8 are shownthreaded in FIG. 1, although alternate embodiments are shown in otherfigures and are discussed herein.

Insulating case 4 contains the electronics, which may include a batteryor other energy storage device and signal generating or receivingcircuitry and is made of an electrically insulating material that iscapable of being hermetically sealed and that is also biocompatible,such as plastic or ceramic. The plastic may be epoxy, polycarbonate, orplexiglass. The ceramic may be alumina, glass, titania, zirconia,stabilized-zirconia, partially-stabilized zirconia, tetragonal zirconia,magnesia-stabilized zirconia, ceria-stabilized zirconia,yttria-stabilized zirconia, or calcia-stabilized zirconia, and in apreferred embodiment, insulating case 4 is yttria-stabilized zirconia,although other insulating materials may also be used. The insulatingcase 4 must be a material that is biocompatible as well as capable ofbeing hermetically sealed, to prevent permeation of bodily fluids intothe case.

The electrically conductive case end 6 is preferably a biocompatible,non-corrosive material, such as titanium or a titanium alloy, althoughother metals such as platinum, iridium, platinum-iridium, stainlesssteel, tantalum, niobium, or zirconium may be used. The preferredmaterial is Ti-6 Al-4 V. An alternate preferred material isplatinum-iridium.

If any electrically conductive electrode is not being used while thestimulator is in the body, then the electrode may be insulated toprevent stimulation of nearby tissue. Protective nut 10 is either aninsulator or an electrically conductive conductor. If it is anelectrical conductor, then it is an extension electrode of electricallyconductive case 6. It is placed over the unused electrically conductiveelectrode 8 such that protective nut threaded hole 12 is tightly screwedonto threaded electrically conductive electrode 8. In a preferredembodiment, the threads on threaded electrically conductive electrode 8are 0-80 threads. In order to avoid growth of tissue into joints, suchas the joint formed between protective nut 10 and electricallyconductive case end 6, it is preferable that any gap be less than 7microns.

An alterative embodiment is illustrated in FIG. 2 where bayonetelectrode 14 is covered by protective nut 15 that contains bayonet mount16. Yet another embodiment of miniature stimulator 2 is illustrated inFIG. 3, where electrically conductive electrode 8 is now stud electrode21, a smooth stud, which has electrode through-hole 18 passing radiallythrough and intersecting with the longitudinal axis of stud electrode21. Stud protective nut 19 is placed onto stud electrode 21 such thatprotective nut mounting hole 20 fits over stud electrode 21 whileprotective nut through-hole 22 is aligned with electrode through-hole18. Protective nut through-hole 22 is positioned such that it passesradially through and intersects with the longitudinal axis of protectivenut 19 and such that nut 19 fits very snugly against electricallyconductive case end 6. Breakaway pin 24 is placed into protective nutthrough-hole 22 and into electrode through-hole 18. After alignment ofprotective nut 19 onto electrode 21 is complete, the protruding portionof breakaway pin 24 is broken off and discarded.

A preferred method of attaching an electrically conductive wire 38 to aminiature stimulator 2 (see FIG. 1) is illustrated in FIGS. 4, 5, and 6wherein flare nut 26 is comprised of protective nut 28, which containsflare nut mounting hole 30. Threaded flare nut mounting hole 30 ispositioned over electrode 8 (see FIG. 1) and tightened by screwing ontothe threads. Flare nut 26 also contains flare nut wire receptor 32 whichhas flare 34 on its extension pointed away from protective nut 28.Because of the small diameter of wire used in this application, flare 34is provided for ease of placement of electrically conductive wire 38into flare 34. Offset through-hole 36 passes through flare nut wirereceptor 32 in a plane that is perpendicular to the longitudinal axis offlare nut 26. Offset through-hole 36 preferably does not intersect withthe longitudinal axis of nut 26, but is intentionally offset topenetrate wire insulator 41 (see FIG. 6) and to intersect with the outerdiameter of wire conductor 40. Thus when a pin, not illustrated, isplaced in offset through-hole 36, wire conductor 40 is contacted,creating an electrically conductive path between wire conductor 40 andprotective nut 28.

The cross-sectional view of FIG. 5 illustrates the offset alignment ofoffset through-hole 36 with respect to the longitudinal axis of flarenut wire receptor 32. Wire conductor 40 is intersected by offsetthrough-hole 36 such that wire insulator 41 will be penetrated and wireconductor 40 will be contacted by a pin inserted in offset through-hole36. Electrically conductive wire 38, shown in FIG. 6 is comprised ofwire conductor 40 within wire insulator 41. Alternately, wire insulator41 may be stripped from an end portion of wire conductor 40, to helpinsure good electrical contact between conductor 40 and flare nut wirereceptor 32.

In a preferred embodiment, wire conductor 40 is a highly conductivemetal that is also benign in the body, such as MP35, although stainlesssteel or an alloy of platinum-iridium may also be used. Preferably, thewire has a diameter of approximately 0.003 inches. It is contained inwire insulator 41 to electrically isolate it from the body tissue andfluids and, in a preferred embodiment, wire insulator 41 isTeflon-coated silicone.

An alternate method of attaching an electrically conductive wire (notshown) to electrically conductive case end 6 is shown in FIG. 7, wherean electrically conductive wire is attached to smooth stud electrode 21by placing smooth protective nut 42 over stud electrode 21 by aligningprotective nut mounting hole 43 with stud electrode 21 and engagingthem. Offset through-hole 44 is of a diameter that allows an insulatedwire to pass therethrough and it is aligned such that when smoothprotective nut 42 is pushed onto stud 21, the electrically conductivewire is contacted and crushed, thereby making electrical contact betweenthe electrically conductive wire and stud electrode 21. Across-sectional view through protective nut 42, illustrated in FIG. 8,shows the alignment of offset through-hole 44 with respect to protectivenut mounting hole 43. Smooth protective nut 42 is retained on stud 21 byvirtue of the frictional force generated by a crushed wire present inoffset through-hole 44 as protective nut 42 is placed on stud electrode21.

In an alternate embodiment, shown in FIG. 9, miniature stimulator 2 hasat one end threaded electrically conductive electrode 8 and at the otherend threaded electrode hole 46. Alternate embodiments contain variouscombinations of electrically conductive electrodes 8 and electrode holes46. FIG. 9 illustrates one such combination of dissimilar electrodes. Asdiscussed previously, if an electrode is unused, then it must be coveredand protected to prevent tissue damage or undesirable tissue growth intothe stimulator. If threaded electrode hole 46 is unused, then it isfilled with electrode plug 48, which is screwed tightly into hole 46, asillustrated in FIG. 10.

A further method of attaching an electrically conductive wire 38 (notillustrated) to electrically conductive case end 6 is illustrated inFIG. 11, where threaded electrode hole 46 mates with smooth nut 52 byinserting threaded insert 50 into threaded electrode hole 46. As nut 52is tightened, an electrically conductive wire, not illustrated, that haspreviously been inserted in smooth nut through-hole 54 is crushedbetween electrically conductive case end 6 and nut crush lip 56, therebymaking contact between the electrically conductive wire and electricallyconductive case end 6. Smooth nut through-hole 54 retains the wire inposition and assures that the wire is secured in place until smooth nut52 is fully tightened.

Illustrated in FIG. 12 is an alternate embodiment of a method ofattaching an electrically conductive wire to a miniature stimulator 2,wherein electrically conductive case end 6 has threaded electricallyconductive electrode 8 attached thereto. Electrically conductiveelectrode 8 contains electrode through-hole 18 located proximate toelectrically conductive case end 6. Protective nut 10 is attached tothreaded electrically conductive electrode 8 by screwing electricallyconductive electrode 8 into protective nut threaded hole 12. Anelectrically conductive wire, not shown, is held in place by placing itthrough electrode through-hole 18. The wire makes electrical contactwith electrically conductive case end 6 by virtue of being crushedbetween electrically conductive case end 6 and protective nut 10 by nutcrush lip 56.

A further embodiment of methods to attach an electrically conductivewire (not illustrated) to assure electrical conductivity between theelectrically conductive wire and the electrically conductive case end 6is illustrated in FIG. 13, where spade clip 58, which is attached to anelectrically conductive wire (not illustrated), is securedly fastenedbetween protective nut 10 and electrically conductive case end 6.

Spade clip 58 is shown in FIG. 14 with tab 60 configured to attach toelectrically conductive wire 38. Electrically conductive wire 38, isplaced in tab 60 with wire insulator 41 stripped from an end portion ofthe electrically conductive wire 38, thereby exposing wire conductor 40for electrical contact with tab 60. Tab 60 is wrapped aroundelectrically conductive wire 38 so as to assure that electricallyconductive wire 38 is securely attached to spade clip 58 by wrapped tab60, which has crimp 70, as shown in FIG. 15.

FIG. 15 illustrates spade clip 58 with electrically conductive wire 38attached to spade clip 58 and retained by crimp 70. Opening 62 in spadeclip 58 is configured to approximate the diameter of electricallyconductive electrode 8 (see FIG. 13) such that spade clip 58 fits overelectrically conductive electrode 8 (not illustrated). In a preferredembodiment, tab 60 and electrically conductive wire 38 are oriented at aright angle to spade clip 58, thus assuring that electrically conductivewire 38 is parallel to the longitudinal axis of miniature stimulator 2,thereby minimizing stresses in the wire. FIGS. 15A and 15B illustratedetailed alternate crimp 70 attachment methods of securedly fasteningwire conductor 40 to spade clip 58.

An alternate embodiment, illustrated by cross-sectional view in FIG. 16,has a wire (not shown) placed through smooth nut through-hole 54, whichis located proximate to smooth nut 52. As smooth nut 52 is tightenedinto threaded electrode hole 46 by inserting threaded insert 50 intothreaded electrode hole 46, the wire is crushed between end crush lip 72and cap 52, thereby making electrical contact between the wire andelectrically conductive case end 6. The difference between the method ofwire attachment illustrated in FIG. 11 and that shown by FIG. 16 is therelocation of nut crush lip 56 from the protective nut 10 of FIG. 11 toelectrically conductive case end 6, as end crush lip 72 in FIG. 16.

Illustrated in FIGS. 18 and 19 is a further embodiment of a method ofattaching an electrically conductive wire (not shown) to miniaturestimulator 2, wherein smooth electrode 76 contains no threads and alsohas offset electrode through-hole 75, which is aligned to lie in a planethat is perpendicular to the longitudinal axis of miniature stimulator 2to intersect with the outer diameter of wire conductor 38, such thatwhen a pin (not shown) is placed in through-hole 75, it will contactwire conductor 40, either by penetrating wire insulator 41 or bycontacting the wire conductor 40 directly, if wire insulator 41 has beenstripped from that area. Protective nut 10, shown in FIG. 19,illustrates nut crush lip 56, and also illustrates offset protective nutmounting hole 77, which aligns with offset electrode through-hole 75,thereby allowing a pin (not shown) to pass through both offsetprotective nut mounting hole 77 and offset electrode through-hole 75.

A further embodiment, illustrated by cross-sectional view in FIG. 20, issimilar to the embodiment presented in FIG. 4, but with electricallyconductive case end 6 having threaded electrode hole 46 in place offlare nut mounting hole 30. Threaded insert 50 is screwed into threadedelectrode hole 46, thereby securing protective nut 28 to electricallyconductive case end 6. An electrical connection between electricallyconductive wire 38 is made by stripping wire insulator 41 from the endof wire 38 thus exposing wire conductor 40. Conductor 40 is insertedinto flare nut wire receptor 32 using flare 34 as a guide. Wireinsulator 41 is stripped such that, when wire conductor 40 is insertedfully into flare nut wire receptor 32, wire insulator 41 extendsapproximately one-quarter of the length of receptor 32 into receptor 32.Wire 38 is securedly attached inside receptor 32 by crimping receptor 32to wire conductor 40.

An alternate method of attaching protective nut 28 to smooth studelectrode 21 is illustrated in FIG. 21. While the preferred method ofattaching the two components is by screwing them together, asillustrated in FIGS. 4 and 20, in the instant embodiment, electricallyconductive case end 6 has stud electrode 21 attached thereto, which hasno threads. Protective nut 28 slips snugly over stud electrode 21 untilelectrically conductive case end 6 is located touching adjoiningprotective nut 28. As previously illustrated in FIG. 20 and as discussedabove, wire 38 and its conductor 40 and wire insulator 41 are securelyfitted inside flare nut wire receptor 32 by using flare 34 as a guide.Electrically conductive wire 38 is secured by crimping flare nut wirereceptor 32 onto wire conductor 40 (see FIG. 21). Protective nut 28 issecured to stud electrode 21 by placing C-clip 74 (see FIG. 17) overprotective nut 28 such that protective nut 28 is partially deformed,thereby creating a secure attachment between stud electrode 21 andprotective nut 28.

The preferred method of assuring electrical insulation betweenelectrically conductive case end 6, electrically conductive electrode 8,protective nut 28, and wire 38, as illustrated in FIG. 22, is to coverthe electrically conductive case end 6 and other parts with rubber boot82. Rubber boot 82 is made of a flexible insulating material that isbiocompatible, such as silicone. Its purpose is to provide electricalinsulation such that stray electrical signals do not pass betweensurrounding tissue and any electrically conductive part of the device.Rubber boot 82 is secured to the device, preferably by tying it in placewith ties 84. A sufficient number of ties 84 are placed by the surgeonto assure that that the rubber boot 82 will not move. It is preferredthat at least one tie 84 and, preferably two or more ties 84, be placedon rubber boot 82 to secure rubber boot 82 to insulating case 4, so asto electrically insulate electrically conductive case end 6 from theliving tissue. FIG. 22A illustrates a typical tie 84 interacting withrubber boot 82, so as to establish and maintain a hermetic seal.Alternate methods of attaching rubber boot 82 include the use of ridgesinside rubber boot 82, clamps over rubber boot 82, silicone adhesiveinside rubber boot 82, ridges on the outside of insulating case 4, amale notch with matching female indentation forming an O-ring seal, andthe tight fit of rubber boot 82 over the device, either with or withoutinternal ridges.

An alternate configuration to miniature stimulator 2, previouslyillustrated in FIG. 1, is miniature disk stimulator 86, which isillustrated in FIGS. 23 and 24. Disk 88 is preferably comprised ofinsulating material having at least one electrically conductiveelectrode 90. Two electrodes are illustrated in FIGS. 23 and 24, butalternate arrangements have at least one, e.g., 1 to 8 or more,electrodes. Electrode 90 is hermetically bonded to disk 88. Electrode 90can be one or more tabs as shown in FIG. 23, or it can be one or moreflush electrodes (not illustrated) that are mounted on the surface ofdisk 88. While the tabs 90 that are illustrated in FIGS. 23 and 24project from the surface of the insulating disk 88, the tabs 90 canequally well not project from the surface of insulating disk 88 and maybe contiguous with the surface such that they do not project above thesurface. The methods of connecting a wire to the miniature stimulatorthat have been previously discussed are equally applicable to miniaturedisk stimulator 86, as well as to other configurations. The dimensionsof disk 88 are about 5 to 40 mm diameter and about 1 to 6 mm thick.Electrically conductive electrode 90 is preferably made of an electricalconductor that is biocompatible and corrosion resistant, such asplatinum, iridium, platinum-iridium, tantalum, titanium or a titaniumalloy, stainless steel, niobium, or zirconium. Disk 88 is made of anelectrical insulator that is biocompatible, such as ceramic, glass, orplastic.

FIG. 25 illustrates an alternate annular electrode arrangement on theend of miniature stimulator 2. At least one annular electrode may beused, e.g., four annular electrodes 92 are illustrated in FIG. 25. Eachannular electrode 92 is capable of carrying an independent electricalsignal and is electrically isolated from the other electrodes. Thesignal from or to stimulator 2 passes along electrically conductivewires 38, where each electrically conductive wire 38 carries anindependent signal and is electrically isolated from the others. Eachelectrically conductive wire 38 corresponds with and is connected to oneannular electrode 92 by means of its connecting to toroidal spring 98.Alternatively, toroidal spring 98 may be a semi-circular spring. Annularcap 94 contains toroidal springs 98. Electrically conductive wires 38pass through holes in the end of cap 94. The internal diameter ofannular cap opening 96 approximates but is slightly larger than theouter diameter of stimulator 2. To make a connection between annularelectrode 92 and toroidal spring 98, annular cap 94 is pushed in alongitudinal direction along the axis of stimulator 2 until it is fullyengaged in a position such that electrical contact is made betweenannular electrode 92 and a corresponding toroidal spring 98. Eachtoroidal spring 98 is preferably retained inside annular cap 94 by anannular recession inside annular cap 94 such that during engagement ofstimulator 2 with annular cap 94, the toroidal spring 98 is forced intothe recession, thereby allowing room for smooth engagement of the parts.The alignment of toroidal spring 98 and annular electrode 92 is suchthat each toroidal spring 98 contacts only one corresponding annularelectrode 92.

FIG. 26 illustrates the case end 100 of stimulator 2 and FIG. 27illustrates the end view of annular cap 94. A cross-sectional view ofannular electrode 92 is illustrated in FIG. 28.

Another embodiment for making an electrical connection to miniaturestimulator 2 is illustrated in FIGS. 29 and 30. FIG. 29 illustrates anend view of electrode plug 104 (see FIG. 30) showing four electricallyconductive wires 38 passing into the center of electrode plug 104through potting material 106. The potting material provides a secure,hermetic seal for wires 38 to pass into miniature stimulator core 102,as illustrated in FIG. 30.

FIG. 30 illustrates a longitudinal view in cross-section of miniaturestimulator 2 comprising insulating case 4, electrically conductive caseend 6, electrode plug 104, and potting material 106. Electrode plug 104is made of a biocompatible material such as titanium and is attached byweld 105 to electrically conductive case end 6, thereby forming ahermetic seal.

Another embodiment for making an electrical connection to a miniaturestimulator 2 is illustrated in FIG. 31 where doorknob electrode 108 isintimately attached to electrically conductive case end 6. The doorknobelectrode is made of a material that is electrically conductive andbiocompatible, such as titanium. Spring clip 110 is preferably a clipmade of titanium which has two or more, and preferably three or fourprongs. Wire insulator 41 is stripped from the end of wire 38 therebyexposing wire conductor 40. Wire conductor 40 is preferably attached tospring clip 110 by strain relief weld 112. Strain relief weld 112 helpsto relieve strain in wire conductor 40 by virtue of being orientedperpendicular to the longitudinal axis of miniature stimulator 2.Further strain relief is provided in wire conductor 40 by virtue of itbeing tightly coiled inside wire insulator 41 thereby forming wirestrain relief 114. The inside of wire insulator 41 is fill material 115,which is preferably soft silicone, to minimize infiltration of bodyfluids and other tissue inside wire 38.

A perspective view of doorknob electrode 108, showing its end attachedto electrically conductive case end 6, is illustrated in FIG. 32. FIG.33 illustrates a perspective view of spring clip 110 showing the fourprongs that slip over doorknob electrode 108 to form an electricalconnection.

FIG. 34 illustrates spring clip 110 together with electricallyconductive wire 38, which in turn is attached by strain relief weld 112to wire conductor 40. Spring clip 110 is shown in its attached positionon doorknob electrode 108. Rubber boot 82 is securely fastened to thedevice with ties 84 to completely cover electrically conductive case end6, doorknob electrode 108, wire conductor 40 and a portion of wireinsulator 41, thus electrically insulating the body tissue fromelectrical signals.

An alternate embodiment is presented in FIG. 35, which is similar to theconnection device presented in FIG. 34 except that connector crimp 118,which is selected from the group of biocompatible materials, and ispreferably platinum metal, is placed over the end of electricallyconductive wire 38 so as to cover a portion of wire insulator 41 andstripped wire conductor 40. Connector crimp 118 is attached toelectrically conductive wire 38 by crimping it onto wire 38.

A preferred embodiment is shown in FIG. 36 in which slip-on cap 122 hasa slightly larger internal diameter of a portion of slip-on cap 122 suchthat it slips over the outer diameter of insulating case 4. Snap-on cap120 has at least one flexible member 130 having a tooth 135 on eachflexible member 130. Tooth 135 engages the edge of electricallyconductive slip-on cap 122, as illustrated in FIG. 37A, and holdssnap-on cap 120 tightly in place. Electrical conductivity is achievedbetween electrically conductive wire 38 and electrically conductiveslip-on cap 122 by spring disk 125 holding enlarged end of wire 140tightly in contact with electrically conductive slip-on cap 122 whensnap-on cap 120 is in place. Rubber boot 82 provides electricalinsulation by covering electrically conductive slip-on cap 122, snap-oncap 120, and a portion of electrically conductive wire 38.

An alternate embodiment is shown in FIG. 37 in which snap-on cap 120 iselongated and slotted on the end opposite tooth 135. When slottedelongated end 123 is squeezed, flexible members 130 are levered outwardand tooth 135 is thereby disengaged from the edge of slip-on cap 122.FIG. 37A illustrates the interaction of tooth 135 with slip-on cap 122such that snap-on cap 120 is securedly fastened to slip-on cap 122.

An alternate embodiment is shown in FIG. 38 in which electricallyconductive case end 6 contains at least one angled flat 150 to allowrotatable cap tooth 136 of rotatable cap 133 to slide smoothly onto theend of electrically conductive case end 6 and to facilitate alignment ofrotatable cap tooth 136 with flat-bottomed slot 145. Electricallyconductive case end 6 has at least one flat-bottomed slot 145 thatengages rotatable cap tooth 136 of rotatable cap 133 to retain rotatablecap 133 on electrically conductive case end 6. When rotatable cap 133 isrotated about its longitudinal axis by about 30° to 90°, rotatable captooth 136 is rotatably moved out of flat-bottomed slot 145, therebyallowing rotatable cap 133 to be removed. These elements are shown inthe perspective views of FIGS. 39 and 40, the angled flat 150 isindicated to facilitate placement of rotatable cap 133 onto electricallyconductive case end 6 in order to engage rotatable cap tooth 136 withflat-bottomed slot 145.

A cross-sectional view, through flat-bottomed slot 145 and perpendicularto the longitudinal axis, is presented in FIGS. 41 and 42. The view ofFIG. 41 indicates the position when rotatable cap 133 is in position toengage rotatable cap tooth 136 with flat-bottomed slot 145. The view ofFIG. 42 indicates the same cross-sectional view as in FIG. 41 butrotatable cap 133 has been rotated 90° from the position illustrated inFIG. 41 to disengage rotatable cap tooth 136 from flat-bottomed slot 145thereby allowing removal of rotatable cap 133.

These various embodiments are of devices and methods for connecting anelectrically conductive wire to a miniature, implantable stimulator inorder to efficiently transmit or receive an electrical signal that isassociated with the implantable stimulator.

Obviously, these methods of attaching a wire to a miniature implantablestimulator can be used in permutations and combinations not specificallydiscussed herein. Many modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically described.

1. A structure, comprising: an implantable miniature device having anelectrically conductive case end and a doorknob electrode coupledthereto for communicating electrical signals between living tissue andsaid device; a spring clip connector having an electrically conductivewire for communicating the electrical signals between said doorknobelectrode and the tissue; and an insulating rubber boot surrounding saidelectrically conductive case end, said doorknob electrode and saidspring clip.
 2. The structure of claim 1 wherein said spring clipconnector is formed of a material selected from the group consisting oftitanium, titanium alloy, platinum, iridium, platinum-iridium, stainlesssteel, tantalum and niobium.
 3. The structure of claim 1 wherein said atleast one electrically conductive case end is a material selected fromthe group consisting of titanium, titanium alloy, platinum, iridium,platinum-iridium, zirconium, niobium, stainless steel, and tantalum. 4.The structure of claim 1 wherein said at least one electricallyconductive case end is comprised of Ti-6Al-4V.
 5. The structure of claim1 wherein said at least one doorknob electrode is a material selectedfrom the group consisting of titanium, titanium alloy, platinum,iridium, platinum-iridium, stainless steel, tantalum and niobium.
 6. Thestructure of claim 1 wherein said insulating rubber boot is comprised ofsilicone.
 7. A structure, comprising: an implantable miniature devicehaving an electrically conductive case end and a doorknob electrodecoupled thereto for communicating electrical signals between livingtissue and said device; a spring clip connector having at least oneprong for grasping said doorknob electrode and adapted for attaching anelectrically conductive wire thereto for communicating the electricalsignals between said doorknob electrode and the tissue; and aninsulating rubber boot surrounding said electrically conductive caseend, said doorknob electrode and said spring clip.
 8. The structure ofclaim 7 wherein said spring clip connector is formed of a materialselected from the group consisting of titanium, titanium alloy,platinum, iridium, platinum-iridium, stainless steel, tantalum andniobium.
 9. The structure of claim 7 wherein said at least oneelectrically conductive case end is a material selected from the groupconsisting of titanium, titanium alloy, platinum, iridium,platinum-iridium, zirconium, niobium, stainless steel, and tantalum. 10.The structure of claim 7 wherein said at least one electricallyconductive case end is comprised of Ti-6Al-4V.
 11. The structure ofclaim 7 wherein said at least one doorknob electrode is a materialselected from the group consisting of titanium, titanium alloy,platinum, iridium, platinum-iridium, stainless steel, tantalum andniobium.
 12. The structure of claim 7 wherein said insulating rubberboot is comprised of silicone.
 13. A structure, comprising: animplantable miniature device having an electrically conductive case endand a doorknob electrode coupled thereto for communicating electricalsignals between living tissue and said device; a spring clip connectoradapted for attaching an electrically conductive wire thereto forcommunicating the electrical signals between said doorknob electrode andsaid spring clip connector, said spring clip connector formed of amaterial selected from the group consisting of titanium, titanium alloy,platinum, iridium, platinum-iridium, stainless steel, tantalum andniobium; and an insulating rubber boot surrounding said electricallyconductive case end, said doorknob electrode and said spring clip. 14.The structure of claim 13 wherein said at least one electricallyconductive case end is a material selected from the group consisting oftitanium, titanium alloy, platinum, iridium, platinum-iridium,zirconium, niobium, stainless steel, and tantalum.
 15. The structure ofclaim 13 wherein said at least one electrically conductive case end iscomprised of Ti-6Al-4V.
 16. The structure of claim 13 wherein saidinsulating rubber boot is comprised of silicone.
 17. A structure,comprising: an implantable miniature device having an electricallyconductive case end and a doorknob electrode electrically coupledthereto for communicating electrical signals between living tissue andsaid device; a spring clip means for grasping said doorknob electrode,said spring clip means comprising an electrically conductive wire forcommunicating the electrical signals between living tissue and saiddevice; and an insulating rubber boot means for insulating saidelectrically conductive case end, said doorknob electrode and saidspring clip against exposure to an environment in which the device isimplanted.
 18. The structure of claim 17 wherein said at least oneelectrically conductive case end is a material selected from the groupconsisting of titanium, titanium alloy, platinum, iridium,platinum-iridium, zirconium, niobium, stainless steel, and tantalum. 19.The structure of claim 17 wherein said at least one electricallyconductive case end is comprised of Ti-6Al-4V.
 20. The structure ofclaim 17 wherein said spring clip means is formed of a material selectedfrom the group consisting of titanium, titanium alloy, platinum.iridium, platinum-iridium, stainless steel, tantalum and niobium. 21.The structure of claim 17 wherein said at least one doorknob electrodeis a material selected from the group consisting of titanium, titaniumalloy, platinum, iridium, platinum-iridium, stainless steel, tantalumand niobium.
 22. The structure of claim 17 wherein said insulatingrubber boot means is comprised of silicone.
 23. A structure, comprising:an implantable miniature device having an electrically conductive caseend and a doorknob electrode for communicating electrical signalsbetween living tissue and said device; means for attaching anelectrically conductive wire to said doorknob electrode forcommunicating the electrical signals between said doorknob electrode andthe tissue, said means comprising a spring clip comprised of at leastone prong for grasping said doorknob electrode; and means for insulatingsaid electrically conductive case end, said doorknob electrode and saidspring clip.
 24. The structure of claim 23 wherein said at least oneelectrically conductive case end is a material selected from the groupconsisting of titanium, titanium alloy, platinum, iridium,platinum-hidlufli, zirconium, niobium, stainless steel, and tantalum.25. The structure of claim 23 wherein said at least one electricallyconductive case end is comprised of Ti-6Al-4V.
 26. The structure ofclaim 23 wherein said at least one doorknob electrode is a materialselected from the group consisting of titanium, titanium alloy,platinum, iridium, platinum-iridium, stainless steel, tantalum andniobium.
 27. The structure of claim 23 wherein said means for insulatingis comprised of a rubber boot.
 28. The structure of claim 23 whereinsaid spring clip means is formed of a material selected from the groupconsisting of titanium, titanium alloy, platinum, iridium,platinum-iridium, stainless steel, tantalum and niobium.